This invention relates to improvements in a ground-fault detector for detecting ground-fault currents flowing through a power distribution line by means of a zero phase-sequence current transformer.
Conventional ground-fault detector of the type referred to could be prevented from performing malfunction due to surges or noise by having the considerably high resistor and/or capacitor for absorbing the surges or noise. This has led to an increase in a time constant involved to impede the high speed operation of the ground-fault detector required for preventing electric shocks so that a high ground-fault current may flow through the human body for a long time. Therefore a danger may occur that a person or persons would be caused to die.